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Mail Archives: djgpp-workers/2013/05/01/06:04:45

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Date: Wed, 01 May 2013 12:04:55 +0200
From: Juan Manuel Guerrero <juan DOT guerrero AT gmx DOT de>
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To: djgpp-workers AT delorie DOT com
Subject: The encoding of S_IFREG
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Reply-To: djgpp-workers AT delorie DOT com

While I was trying to port patch 2.7.1, besides a lot of issues, I 
encountered
the following problem:  DJGPP file mode encodes S_IFREG with 0x0000.
Unfortunately the patch code checks if the file mode is valid at all by
checking against zero.  This means that if the file mode extracted from the
diff file (for git style patches) or the file mode returned by the stat
structure is zero it aborts.  Of course, I have fixed this by also checking
with S_ISREG so I can avoid the program stop or erratic behaviour.
An inspection of my linux stat.h shows that no valid combination of 
S_IF* bits
will ever lead to a file mode identical to zero.
Is there any particular reason why DJGPP does encode S_IFREG with zero?
Are there any objections if this is changed?


Currently the following encodings are used:

#define S_IFMT        0xf000

#define S_IFREG        0x0000
#define S_IFBLK        0x1000
#define S_IFCHR        0x2000
#define S_IFDIR        0x3000
#define S_IFIFO        0x4000
#define S_IFLNK         0x8000

#define S_IFLABEL    0x5000

We could replace 0x0000 by 0x6000.  I am aware that this may introduce 
backward
incompatibilities, but I think that nowadays the group of DJGPP users is so
vanishing that this change will not really harm some one.  But the benefits
when a porting job is done are evident.

Regards,
Juan M. Guerrero

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